Partially hydrolyzed guar gum in pediatric functional abdominal pain

AIM:To assess the effects of partially hydrolyzed guar gum(PHGG) diet supplement in pediatric chronic abdominal pain(CAP) and irritable bowel syndrome(IBS).METHODS:A randomized,double-blind pilot study was performed in sixty children(8-16 years) with functional bowel disorders,such as CAP or IBS,diagnosed according to Rome Ⅲ criteria.All patients underwent ultrasound,blood and stool examinations to rule out any organic disease.Patients were allocated to receive PHGG at dosage of 5 g/d(n = 30) or placebo(fruitjuice n = 30) for 4 wk.The evaluation of the efficacy of fiber supplement included IBS symptom severity score(Birmingham IBS Questionnaire),severity of abdominal pain(Wong-Baker Face Pain Rating Score) and bowel habit(Bristol Stool Scale).Symptom scores were completed at 2,4,and 8 wk.The change from baseline in the symptom severity scale at the end of treatment and at 4 wk follow-up after treatment was the primary endpoint.The secondary endpoint was to evaluate compliance to supplementation with the PHGG in the pediatric population.Differences within groups during the treatment period and follow-up were evaluated by the Wilcoxon signed-rank test.RESULTS:The results of the study were assessed considering some variables,such as frequency and intensity of symptoms with modifications of the bowel habit.Both groups were balanced for baseline characteristics and all patients completed the study.Group A(PHGG group) presented a higher level of efficacy compared to group B(control group),(43% vs 5%,P = 0.025) in reducing clinical symptoms with modification of Birmingham IBS score(median 0 ± 1 vs 4 ± 1,P = 0.025),in intensity of CAP assessed with the Wong-Baker Face Pain Rating Score and in normalization of bowel habit evaluated with the Bristol Stool Scale(40% vs 13.3%,P = 0.025).In IBS subgroups,statistical analysis shown a tendency toward normalization of bowel movements,but there was no difference in the prevalence of improvement in two bowel habit subsets.PHGG was therefore better tolerated without any adverse effects.CONCLUSION:Although the cause of pediatric functional gastrointestinal disorders is not known,the results show that complementary therapy with PHGG may have beneficial effects on symptom control.

Effect of Dietary Supplementation with Hydrolyzed Wheat Gluten on Growth Performance, Cell Immunity and Serum Biochemical Indices of Weaned Piglets (Sus scrofa)

To investigate the effects of dietary supplementation with hydrolyzed wheat gluten （HWG） on growth performance, cell immunity and serum biochemical indices of weaned piglets, 160 crossed （Large White×andrace） and weaned piglets were randomly divided into 4 treatments with 4 replicates of 10 piglets each. The piglets in each treatment were fed an experimental diet containing either 0 g kg-1 HWG （control group）, 30 g kg-1 HWG （3% HWG group）, 50 g kg-1 HWG （5% HWG group）, or 2.5 g kg-1 glycyl-L-glutamine （0.25% Gly-Gln group）. The results showed that the diarrhea rates in 3% HWG and 5% HWG groups were significantly lower than in control group from d 1 to 14 （P〈0.05）, while the average daily gain （ADG） in each of two groups was increased （P〉0.05）. When compared with control group, dietary supplementation with 3% HWG increased the ratio of CD4＋：CD8＋ and the ratio of serum albumin and globulin concentrations （A：G） on d 14 and 28, as well as the proliferation of T- and B-lymphocytes （P〉0.05） on d 28. In addition, on d 14 and 28, the A：G ratio in 5% HWG group was significantly higher than in control group （P〈0.05）, while the ratio of CD4＋：CD8＋ increased slightly （P〉0.05）. Interestingly, 0.25% Gly-Gln group had higher proportion of CD3＋ （P〉0.05） and CD4＋ （P〈0.05） on d 14 than control group, but growth performances of 0.25% Gly-Gln group were negatively affected at all experiment stages. These results suggested that HWG might improve the growth performance of piglets by strengthening cell immunity and decreasing the occurrence of diarrhea during the prophase after weaning.

Effect of salt solutions on chain structure of partially hydrolyzed polyacrylamide

The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction between CaCl2 solution and HPAM was also researched.Experimental results show that the chain structure of HPAM is interrelated with the charge density,the kind and the concentration of salt solutions.The mean-square radius of gyration(Rz) and the second virial coefficient(A2) of HPAM decrease with increasing concentration of salt solutions,and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount.

Adaptation fermentation of Pichia stipitis and combination detoxification on steam exploded lignocellulosic prehydrolyzate

Yeast Pichia stipitis CBS 5776 was developed through adaptation fermentation step by step in steam exploded corn stover prehydrolyzate because high concentration of weak acids and other inhibitors present in the prehydrolyzate could degrade the fermentability. However, the adaptability of Pichia stipitis CBS 5776 in the prehydrolyzate was so limited that steam strip-ping and overliming were applied to remove these inhibitors from it. Corn stover was steam exploded;the filtrate of steam exploded corn stover was hydrolyzed with dilute sulfuric acid, and then the acid hydrolyzate was detoxified and fermented by Pichia stipitis CBS 5776. Steam stripping could remove volatile com-pounds from the acid hydrolyzate and the fil-trate. At a steam stripping time of 120min, 81% acetic acid and 59% formic acid were removed from the acid hydrolyzate, 77% acetic acid and 45% formic acid were removed from the filtrate, while furfural was stripped off completely from the acid hydrolyzate and the filtrate. Overliming could reduce the contents of furfural and phe-nolics present in the acid hydrolyzate, however, sugars, especially pentoses, were also removed partially. It was necessary to detoxify the acid hydrolyzate in order to ferment the sugars to ethanol. Acid hydrolyzate detoxified with a combination of steam stripping for 120 min and overliming at pH11 and 60℃ for 90 min, its fer-mentability was significantly improved. Xylose was consumed nearly completely in 24h with an ethanol yield of 15.92g/l, 80.34% of theoretical.

Separation of diaspore from bauxite by selective flocculation using hydrolyzed polyacrylamide

Selective flocculation is a new method to solve the problem of China's bauxite de-silication besides flotation and reverse flotation. The method of selective flocculation of bauxite using hydrolyzed polyacrylamide as flocculant was experimented and evaluated. The results of diaspore and kaolinite single mineral settling tests show that the difference between settlement yield of kaolinite(settling 15 min) and diaspore(settling 3 min) increases from 16% to 60% by adding flocculant at pH=7. Results of selective flocculation experiment of bauxite show that the higher concentrate grade(65.75) and Al-Si ratio(7.34) could be obtained with sodium carbonate as dispersant compared with sodium hexametaphosphate; under the action of flocculating agent, the concentrate grade and Al-Si ratio increase to 67.99 and 9.01. These results could meet the requirements of Bayer production, and the simpler process was expected to cost far less than traditional flotation method and a promising de-silication method of bauxite.

Partially hydrolyzed guar gum attenuates non-alcoholic fatty liver disease in mice through the gut-liver axis

BACKGROUND The gut-liver axis has attracted much interest in the context of chronic liver disease pathogenesis.Prebiotics such as dietary fibers were shown to attenuate non-alcoholic fatty liver disease(NAFLD)by modulating gut microbiota.Partially hydrolyzed guar gum(PHGG),a water-soluble dietary fiber,has been reported to alleviate the symptoms of various intestinal diseases and metabolic syndromes.However,its effects on NAFLD remain to be fully elucidated.To determine whether treatment with PHGG attenuates NAFLD development in mice through the gut-liver axis.METHODS Seven-week-old male C57BL/6J mice with increased intestinal permeability were fed a control or atherogenic(Ath)diet(a mouse model of NAFLD)for 8 wk,with or without 5%PHGG.Increased intestinal permeability was induced through chronic intermittent administration of low-dose dextran sulfate sodium.Body weight,liver weight,macroscopic findings in the liver,blood biochemistry[aspartate aminotransferase(AST)and alanine aminotransferase(ALT),total cholesterol,triglyceride,free fatty acids,and glucose levels],liver histology,myeloperoxidase activity in liver tissue,mRNA expression in the liver and intestine,serum endotoxin levels in the portal vein,intestinal permeability,and microbiota and short-chain fatty acid(SCFA)profiles in the cecal samples were investigated.RESULTS Mice with increased intestinal permeability subjected to the Ath diet showed significantly increased serum AST and ALT levels,liver fat accumulation,liver inflammatory(tumor necrosis factor-αand monocyte chemotactic protein-1)and fibrogenic(collagen 1a1 andαsmooth muscle actin)marker levels,and liver myeloperoxidase activity,which were significantly attenuated by PHGG treatment.Furthermore,the Ath diet combined with increased intestinal permeability resulted in elevated portal endotoxin levels and activated toll-like receptor(TLR)4 and TLR9 expression,confirming that intestinal permeability was significantly elevated,as observed by evaluating the lumen-to-blood clearance of fluorescein isothiocyanate-conjugated dextran.PHGG treatment did not affect fatty acid metabolism in the liver.However,it decreased lipopolysaccharide signaling through the gut-liver axis.In addition,it significantly increased the abundance of cecal Bacteroides and Clostridium subcluster XIVa.Treatment with PHGG markedly increased the levels of SCFAs,particularly,butyric acid,acetic acid,propionic acid,and formic acid,in the cecal samples.CONCLUSION PHGG partially prevented NAFLD development in mice through the gut-liver axis by modulating microbiota and downstream SCFA profiles.

Oxidation of Partially Hydrolyzed Polyacrylamide from Polymer Flooding Processes Using Fenton Reagents

The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.

INTERACTION OF COMPONENTS IN PETROLEUM CARBOXYLATE/ALKALINE/HYDROLYZED POLYACRYLAMIDE FLOODING SYSTEM

The IFTs(Interfacial tension)of petroleum carboxylate/alkaline/HPAM(Hydrolyzed polyacrylamide)flooding system with Daing crude oil and the effects of petroleum carboxylate and alkaline on viscoaity of HPAM solution were studied.There exists remarkable synergism between HPAM and petroleum carboxylate,and the introduction of HPAM into petroleum carboxylate/alka- line system leads the lowering of IFTs against Daqing crude oil,The introduction of petroleum carboxylate into solution of HPAM also leads the decreasing of viscosity,but the extent of viscosity decreasing is much lower than that caused by inorganic salts such as NaCl and CaCl_2.

Effect of N fertilization rate on soil alkalihydrolyzable N, subtending leaf N concentration,fiber yield, and quality of cotton

Soil alkali-hydrolyzable nitrogen, which is sensitive to N fertilization rate, is one of the indicators of soil nitrogen supplying capacity. Two field experiments were conducted in Dongtai(120°19″ E, 32°52″ N), Jiangsu, China in 2009 and Dafeng(120°28″ E, 33°12″ N), Jiangsu province, China in 2010. Six nitrogen rates(0, 150, 300, 375, 450, and 600 kg ha^(-1)) were used to study the effect of N fertilization rate on soil alkali-hydrolyzable nitrogen content(SAHNC), subtending leaf nitrogen concentration(SLNC), yield, and fiber quality. In both Dongtai and Dafeng experiment station, the highest yield(1709 kg ha^(-1)), best quality(fiber length 30.6 mm, fiber strength 31.6 c N tex^(-1), micronaire 4.82), and highest N agronomic efficiency(2.03 kg kg^(-1)) were achieved at the nitrogen fertilization rate of 375 kg ha^(-1). The dynamics of SAHNC and SLNC could be simulated with a cubic and an exponential function,respectively. The changes in SAHNC were consistent with the changes in SLNC. Optimal average rate(0.276 mg day^(-1)) and duration(51.8 days) of SAHNC rapid decline were similar to the values obtained at the nitrogen rate of 375 kg ha^(-1)at which cotton showed highest fiber yield, quality, and N agronomic efficiency. Thus, the levels and strategies of nitrogen fertilization can affect SAHNC dynamics. The N fertilization rate that optimizes soil alkali-hydrolyzable nitrogen content would optimize the subtending leaf nitrogen concentration and thereby increase the yield and quality of the cotton fiber.

The Hydrolyzation of Collagen by Fucoidan Olisosaccharide's Complex with Ce^(IV)

Fucoidan is such a polysaccharide that its hydroxies are easy to combine with lanthanons ion （Ce^IV） to form complex. This work obtained the complexes of three fucoidan oligosaccharides with different molecular weights F1 （〉5 000）, F2 （1 000-5 000） and F3 （〈 1 000） by hydrolyzing Oligosaccharide collagen with sulfuric acid. It is found that the fucoidan oligosaccharide F3 can form complex with more Ce^IV than F1 and F2. Hydrolyzing collagen with the complex was carried out to produce amino acid and peptides. All the three fucoidan oligosaccharide complexes with CeIV（ F1, F2, F3） can catalyze by the artificial hydrolytic enzyme, and the activity of the complex of F3 is the highest.

Hypoallergenicity of a thickened hydrolyzed formula in children with cow’s milk allergy

BACKGROUND Allergy to cow’s milk is the most frequent allergy occurring in infants and young children.The dietary management of these patients consists of the elimination of any cow’s milk proteins from the diet,and for formula-fed infants,the substitution of the usual infant formula with an adapted formula that is generally based on extensively hydrolyzed cow’s milk proteins.The American Academy of Pediatrics has established specific criteria to confirm the hypoallergenicity of a formula intended for these children.AIM To assess the hypoallergenicity of a new thickened extensively hydrolyzed casein-based formula (TeHCF) in children with cow’s milk allergy (CMA).METHODS Children diagnosed with CMA through a double-blind placebo-controlled food challenge (DBPCFC) were randomly administered increased doses of a placebo formula or the TeHCF [Allernova,new thickener including fibres (Novalac)] under double-blind conditions and medical surveillance on two separate days.Otherwise,both of these formulas and a cow’s milk-based formula were randomly introduced to children who were highly suspected of having CMA on three separate days.Immediate and late reactions occurring after the introduction of any of these formulas were thoroughly recorded by the physician at the hospital and reported by parents to the physician after hospital discharge,respectively.If the children tolerated the TeHCF during the DBPCFC,they were exclusively fed this formula during a 3-mo period where potential allergic symptoms,anthropometric parameters,as secondary outcomes,and adverse events were registered.The Cow’s Milk-related Symptoms Score (CoMiSSTM) was assessed and anthropometric parameters were compared to World Health Organization (WHO) reference data.RESULTS Of the 30 children included in the study,the CMA diagnosis of 29 (mean age: 8.03 ± 7.43 mo) patients was confirmed by a DBPCFC.The children all tolerated the TeHCF during both the challenge and the subsequent 3-mo feeding period,which they all completed.During the latter period,the CoMiSSTM remained at a very low level,never exceeding its baseline value (1.4 ± 2.0),growth parameters were within WHO reference standards and no adverse event related to the TeHCF was reported.Over the first week of this period,the proportion of patients with digestive discomfort significantly decreased from 20.7%(6/29) to 3.4%(1/29),P = 0.025.The proportion of satisfaction with the overall effect of the formula reported by the parents and investigator was high,as was the formula acceptability by the child.CONCLUSION The new TeHCF meets the hypoallergenicity criteria according to the American Academy of Pediatrics standards,confirming that the tested TeHCF is adapted to the dietary management of children with CMA.Moreover,growth was adequate in the included population.

Enhanced Redispersibility of Cellulose Nanocrystals in Water via Surface Adsorption of Hydrolyzed Sugars from Corresponding Cellulose Nanocrystal Fabrication

Generally,hydrogen bonds are formed between cellulose nanocrystals(CNCs)during their water removal and drying,leading to the irreversible aggregation of CNCs,and thus a poor water-redispersibility.The present study demonstrated a novel approach that involved using hydrolyzed sugars generated from the corresponding CNC production as redispersing agents to enhance the redispersibility of CNCs.Experimental data indicated that hydrolyzed sugars can be adsorbed onto CNCs through ethanol precipitation.The oven-dried CNCs onto which hydrolyzed sugars were adsorbed via ethanol precipitation were homogeneously redispersed in water.The redispersed CNCs showed the particle size distribution,Zeta potential,and thermal decomposition properties similar to those of the CNCs without drying.This method may improve the use of hydrolyzed sugars obtained in the hydrolysate from the corresponding CNC production,as well as facilitate the transportation and storage of CNCs.

超声辅助酶法提取玉米胚芽粕水解蛋白及其抗氧化活性

以玉米胚芽粕为原料,研究超声波辅助碱性蛋白酶提取玉米胚芽粕水解蛋白的工艺条件。通过单因素试验初步确定超声波辅助酶法提取玉米胚芽粕水解蛋白的条件,在单因素试验基础上进行正交试验设计,并测定其抗氧化活性。结果表明,最优提取条件为超声温度50℃、超声时间50 min、超声功率140 W,在此条件下,玉米胚芽粕的水解蛋白提取率为90.6%。对DPPH自由基和羟自由基的IC_(50)分别为17.56µg/mL和28.41µg/mL。

水汽系统积盐问题分析及处理

尿素水解制氨技术已广泛应用于火电机组脱硝还原剂的制备。然而,若出现尿素质量不合格,尿素水解器发生泄漏以及水解器疏水回用至凝汽器的情况,会对热力系统造成巨大危害。对某燃煤机组尿素水解器泄漏致水汽系统严重积盐及过热器爆管进行了分析,并提出了补充处理方案。实施后机组各项水汽指标均达到《火力发电机组及蒸汽动力设备水汽质量》(GB/T 12145—2016)要求,为水汽系统积盐的原因分析及处理提供了解决方案。

母猪饲粮添加益生菌和合生元对子代巴马香猪肌肉氨基酸组成及生长发育相关基因表达的影响

[目的]本文旨在研究母猪饲粮添加益生菌和合生元对子代巴马香猪肌肉氨基酸组成及相关基因表达的影响。[方法]选用64头妊娠巴马香猪,随机分为对照组(基础饲粮)、抗生素组(50 g·t^(-1)维吉尼亚霉素)、益生菌组(200 mL·d^(-1)益生菌发酵液)和合生元组(500 g·t^(-1)低聚木糖+200 mL·d^(-1)益生菌发酵液),每组16头母猪,单栏饲养。母猪在整个妊娠期和哺乳期饲喂相应试验饲粮;仔猪断奶后,每窝选取2头仔猪,每组32头(8栏,每栏4头),饲喂基础饲粮。分别于65、95和125日龄每组选取8头采集股二头肌和腰大肌样品,测定其水解氨基酸组成和相关基因的表达量。[结果]与对照组相比,合生元组子代巴马香猪股二头肌粗蛋白、Gly、Ser、Ala、Asp、Glu、Pro和Ile含量,腰大肌Gly、Glu、Ser和His含量均显著增加(P<0.05);益生菌组子代巴马香猪股二头肌肌肉萎缩F-box蛋白32和生肌调节因子(MyoG)、腰大肌生肌因子5(Myf5)的表达水平显著上调(P<0.05),腰大肌肌球蛋白重链Ⅱb(MyHCⅡb)、股二头肌和腰大肌肌肉生长抑制素(MSTN)的表达水平显著下调(P<0.05);合生元组子代巴马香猪股二头肌Myf6、生肌分化因子和MyoG以及腰大肌Myf5和MyoG的表达水平显著上调(P<0.05),股二头肌MSTN的表达水平显著下调(P<0.05);益生菌组和合生元组子代巴马香猪股二头肌MyHCⅡx的表达水平显著下调(P<0.05);抗生素组子代巴马香猪腰大肌MyHCⅡx的表达水平显著上调(P<0.05),而股二头肌MyHCⅠ和腰大肌MyHCⅡa的表达水平显著下调(P<0.05)。[结论]母猪饲粮添加益生菌和合生元可改变子代巴马香猪肌肉氨基酸组成,调控生肌因子相关基因表达,上调氧化型肌纤维基因的表达、下调酵解型肌纤维基因的表达,从而有利于肉品质的改善。

长期摄入水解单宁对鼠类生殖的影响

水解单宁(hydrolyzed tannin)是橡子内主要的单宁酸类型,对以橡子为主要食物来源的鼠类的生存繁衍有重要影响.为探究长期取食水解单宁对鼠类的生殖激素与生殖器官产生的影响.选择72只(雌雄个体各36只)4周龄的健康昆明小鼠,随机分为4组,分别为对照组(水解单宁比例为0)、低单宁组(水解单宁比例为2%)、中单宁组(水解单宁比例为7%)和高单宁组(水解单宁比例为12%),用不同水解单宁含量的饲料饲喂42d后解剖取样.结果显示,高含量水解单宁显著降低了雄鼠存活率;中、高含量水解单宁对生殖激素的稳定产生负面效应;高含量水解单宁造成生殖器官损伤,导致小鼠卵巢与睾丸生理结构改变,降低了正常卵泡数量和精子的发生.试验验证了长期摄入高含量水解单宁打破了鼠类的生殖激素平衡且造成了生殖器官的损伤.

海滨木槿种子无菌萌发及壮苗的培养基筛选

海滨木槿是东南沿海地区防风护堤林的首选树种,也是瘠薄山地水保林的良好树种。无菌壮苗的获取是建立高效再生体系的前提,可为植物资源保护和新品种选育提供基础。该研究以MS为基本培养基,比较柠檬酸、活性炭、三碘苯甲酸(TIBA)、6-苄氨基腺嘌呤(6-BA)、萘乙酸(NAA)、水解酪蛋白、维生素H、叶酸、噻苯隆(TDZ)和寡糖·链蛋白等添加物对海滨木槿种子萌发以及壮苗培养的影响。结果显示,种子萌发最佳配方为MS+6-BA 0.5 mg·L^(-1)+NAA 0.1 mg·L^(-1)+水解酪蛋白0.1 g·L^(-1),萌发率从21.4%±7.8%提高到85.3%±9.1%;维生素、叶酸、柠檬酸的添加均未能促进种子的萌发。培养基MS+6-BA 0.1 mg·L^(-1)+寡糖·链蛋白0.1 g·L^(-1)+活性炭0.1%中的幼苗增殖系数最高,达7.0±2.6,且直立生长,茎枝较粗,叶片肥厚。值得注意的是,TDZ和NAA组合诱导出来的材料分化能力较强,可为后期海滨木槿诱导体胚成苗技术研究提供一定的参考。

长期不同施肥模式对大麦–双季稻田根际土壤有机氮组分的影响

根际土壤有机氮组分在土壤养分和作物氮素营养中具有重要作用。本研究依托长期(37年)定位施肥试验田,设置4个施肥处理:不施肥对照(CK)、单独施用化肥(CF)、秸秆还田+化肥(RF)和30%有机肥+70%化肥(OM),于晚稻成熟期测定大麦–双季稻田根际土壤基础理化性质、微生物生物量氮和有机氮组分(氨基酸态氮、氨基糖态氮、酸解氨态氮、酸解未知态氮、非酸解性氮)含量。研究表明:相对CK处理,RF和OM处理显著增加了稻田根际土壤有机碳、全氮、铵态氮和硝态氮的含量。RF和OM处理土壤微生物生物量氮含量分别比CK处理增加了19.8%和30.7%。酸解性氮作为根际土壤全氮的主体部分,占全氮的59.61%~72.06%;各处理根际土壤酸解性氮含量大小顺序表现为OM>RF>CF>CK。各施肥处理中,酸解有机氮中的氨基糖态氮、氨基酸态氮和酸解未知态氮含量均以OM处理最大,分别比CK处理增加139.3%、47.9%和110.0%;酸解氨态氮以RF处理最大,比CK处理增加69.9%。土壤有机碳、全氮、铵态氮、硝态氮与土壤氨基酸态氮、氨基糖态氮、酸解未知态氮以及微生物生物量氮均呈极显著(P<0.01)正相关。因此,秸秆、有机肥配施化肥均能有效提高大麦–双季稻田根际土壤的供氮能力,是改善稻田土壤肥力的有效手段。

部分水解瓜尔胶的酶法制备及其对面包烘焙特性的影响

为研究部分水解瓜尔胶(partially hydrolyzed guar gum,PHGG)对面包烘焙特性的影响,以瓜尔胶(guar gum,GG)为原料,采用酶解法制备PHGG。在比较PHGG和GG基本组成差异的基础上,采用质构仪、低场核磁共振仪、差示扫描量热仪和九分嗜好评分法研究PHGG添加量对面包烘焙品质及储藏特性的影响。基本组成分析结果表明,与GG相比,PHGG的黏度和分子质量显著下降,分别为(118.80±0.62)mPa·s、8.1 kDa。烘焙品质分析结果表明,添加PHGG对面包比容无显著影响,但可显著降低面包的烘焙损失率,从(14.08±0.77)%降低至(11.73±1.29)%;并赋予了面包更好的色泽。面包储藏特性研究结果表明:在7 d储藏期内,PHGG显著提高了面包的保水率,从(77.48±0.43)%增加至(85.58±4.15)%;改善了面包的内聚性和回复性;促进了面包内部水分的迁移,进而增加了面包内部结构的稳定性,具有延缓面包老化的效果。此外,感官评价结果表明,PHGG添加组面包的感官评分高于对照组面包。PHGG添加量(质量分数)为2.5%~4.5%时可显著改善面包的烘焙品质、储藏特性和感官品质,研究旨在为PHGG在食品加工中的应用提供一定理论参考。

鱿鱼加工副产物酶解液美拉德反应工艺优化

鱿鱼加工过程中会产生20%左右的副产物,其中富含蛋白质、氨基酸等多种营养成分和呈味成分。本研究采用双酶酶解工艺制备了鱿鱼加工副产物酶解液,以感官评分为指标,通过单因素和正交试验优化了鱿鱼加工副产物酶解液与大豆多糖-葡萄糖美拉德反应工艺。实验结果表明:在pH值8.0、温度110℃、葡萄糖-多糖添加量4%(ω(葡萄糖)∶ω(大豆多糖)=3∶1)、时间60 min的条件下,酶解液的感官评分值最高,反应产物具有明显的鱿鱼香气,口味鲜美。电子舌结果显示,美拉德处理前后的酶解液风味变化明显,表明美拉德反应可以改善酶解液的味道。本研究为鱿鱼加工副产物的综合利用和水产调味料的开发提供了思路。